rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7654/1:b..l rcu: (detected by 1, t=10502 jiffies, g=28669, q=1532 ncpus=2) task:syz-executor.5 state:R running task stack:26984 pid:7654 tgid:7654 ppid:7078 task_flags:0x400040 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_read_lock include/linux/rcupdate.h:842 [inline] RIP: 0010:class_rcu_constructor include/linux/rcupdate.h:1155 [inline] RIP: 0010:unwind_next_frame+0xcd/0x2390 arch/x86/kernel/unwind_orc.c:479 Code: 00 00 48 c7 c7 60 f0 13 8e 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 41 57 e8 6e 96 2b 00 48 83 c4 08 e8 c5 61 f3 09 85 c0 <74> 3a e8 2c 88 34 00 84 c0 75 31 e8 b3 61 f3 09 85 c0 74 28 80 3d RSP: 0018:ffffc9000be7f578 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff8772c33e RCX: ffff88807c5cda00 RDX: 0000000000000000 RSI: ffffffff8db6e382 RDI: ffffffff8be28280 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff81729de5 R10: dffffc0000000000 R11: ffffffff81acf990 R12: 1ffff920017cfec9 R13: ffffc9000be7f680 R14: ffffc9000be7f648 R15: ffffffff81729de5 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706 discard_slab mm/slub.c:2717 [inline] __put_partials+0x161/0x1c0 mm/slub.c:3186 put_cpu_partial+0x17c/0x250 mm/slub.c:3261 __slab_free+0x2f7/0x400 mm/slub.c:4513 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4340 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] kobject_get_path+0xc5/0x2d0 lib/kobject.c:161 kobject_uevent_env+0x292/0x8c0 lib/kobject_uevent.c:545 device_remove drivers/base/dd.c:567 [inline] __device_release_driver drivers/base/dd.c:1272 [inline] device_release_driver_internal+0x46f/0x7c0 drivers/base/dd.c:1295 driver_detach+0x1f3/0x2d0 drivers/base/dd.c:1358 bus_remove_driver+0x226/0x2f0 drivers/base/bus.c:747 usb_gadget_unregister_driver+0x4e/0x70 drivers/usb/gadget/udc/core.c:1732 raw_release+0xd7/0x260 drivers/usb/gadget/legacy/raw_gadget.c:462 __fput+0x44c/0xa70 fs/file_table.c:465 fput_close_sync+0x119/0x200 fs/file_table.c:570 __do_sys_close fs/open.c:1589 [inline] __se_sys_close fs/open.c:1574 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1574 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f848587bdda RSP: 002b:00007fffd3cf1370 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f848587bdda RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: ffffffffffffffff R08: 00007f8485800000 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000293 R12: 00007f84859b3fa0 R13: 00007f84859b3fac R14: 0000000000000bea R15: 00007f84859b59a0 rcu: rcu_preempt kthread starved for 8427 jiffies! g28669 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:26888 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6 Comm: kworker/R-kvfre Not tainted 6.15.0-syzkaller-13743-g8630c59e9936 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: kvfree_rcu_reclaim kfree_rcu_monitor RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x17/0xb0 kernel/rcu/tree.c:745 Code: 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 e0 b9 f5 10 e8 8b eb be 09 89 c3 <83> f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 60 6c ba RSP: 0018:ffffc900000070b8 EFLAGS: 00000086 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 3fe52fcdba8af700 RDX: ffffc90000007201 RSI: ffffffff8be28260 RDI: ffffffff8be28220 RBP: dffffc0000000000 R08: ffffc900000071f8 R09: ffffc90000007258 R10: dffffc0000000000 R11: fffff52000000e4d R12: ffffc90000007208 R13: ffffc90000000000 R14: ffffc90000007208 R15: ffffffff81729de5 FS: 0000000000000000(0000) GS:ffff888125c52000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f99aa5b0000 CR3: 0000000077d9a000 CR4: 0000000000350ef0 Call Trace: rcu_read_unlock include/linux/rcupdate.h:869 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x1965/0x2390 arch/x86/kernel/unwind_orc.c:680 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359 kmalloc_noprof include/linux/slab.h:905 [inline] dummy_urb_enqueue+0x7c/0x780 drivers/usb/gadget/udc/dummy_hcd.c:1273 usb_hcd_submit_urb+0x325/0x1aa0 drivers/usb/core/hcd.c:1533 ath9k_hif_usb_rx_cb+0x115e/0x1500 drivers/net/wireless/ath/ath9k/hif_usb.c:722 __usb_hcd_giveback_urb+0x41a/0x690 drivers/usb/core/hcd.c:1650 dummy_timer+0x862/0x4550 drivers/usb/gadget/udc/dummy_hcd.c:1994 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1842 handle_softirqs+0x286/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:process_one_work kernel/workqueue.c:3243 [inline] RIP: 0010:process_scheduled_works+0xaeb/0x17b0 kernel/workqueue.c:3321 Code: 44 24 60 42 80 3c 30 00 74 08 4c 89 ef e8 fd b3 97 00 4d 8b 5d 00 48 8b 3c 24 2e e8 af 9c dc 09 48 8b 44 24 60 42 80 3c 30 00 <74> 08 4c 89 ef e8 db b3 97 00 4d 8b 7d 00 0f 1f 44 00 00 e8 bd 3c RSP: 0018:ffffc900000b7a60 EFLAGS: 00000246 RAX: 1ffff11028085a23 RBX: ffffffff818c211f RCX: 0000000000000000 RDX: 0000000000000006 RSI: ffffffff8d9816ba RDI: 00000000ffffffff RBP: ffffc900000b7c60 R08: ffffffff8fa113f7 R09: 1ffffffff1f4227e R10: dffffc0000000000 R11: fffffbfff1f4227f R12: ffff88801a498000 R13: ffff88814042d118 R14: dffffc0000000000 R15: 0000000000000000 rescuer_thread+0x53c/0xdd0 kernel/workqueue.c:3498 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245